In recent years, TAVI (Trans-catheter Aortic Valve Implantation) also referred as TAVR (Trans-catheter Aortic Valve Replacement) using a catheter attracts attention. The procedure in TAVI is performed in the operating room equipped with an X-ray imaging apparatus. That is, TAVI is the technique of placing an artificial valve in the heart of an object, with observing X-ray fluoroscopic images acquired in real time by an X-ray imaging apparatus.
In TAVI, it is important to place an artificial valve on an exact position with referring to X-ray fluoroscopic images. Specifically, it becomes a target to place an artificial valve so that the lower end of the artificial valve lies under the bottom of the original valve while the upper end of the artificial valve lies above the leaflet tip of the original valve and under the coronary arteries.
Then, a technique by which road map images of an object are displayed with an X-ray imaging apparatus is proposed as a technique which supports such TAVI. A road map image is an image made by overlapping a previously acquired X-ray contrast image of blood vessels with an X-ray fluoroscopic image acquired in real time.
In TAVI, contrast medium is generally injected into a blood vessel in advance of placing an artificial valve. Then, X-ray contrast images, on which blood vessels are enhanced blackly, are acquired. Next, in a state where a device such as a guide wire for blood vessel has been inserted, X-ray fluoroscopic images are acquired in real time as live images. Although a device can be seen on these X-ray fluoroscopic images, it is difficult to sight blood vessels.
Accordingly, an X-ray contrast image is used as a mask image, and road map images which are derived by combining the mask image with each of the live images by subtraction processing between the mask image and each of the live images can be generated and displayed. Consequently, a doctor can operate a device to place an artificial valve with referring to contrast blood vessels on the road map images.
Note that, road map images include 2D (two dimensional) road map images and 3D (three dimensional) road map images. A 2D road map image is displayed as a 2D image by 2D data acquisition to generate a 2D intermediate image. On the other hand, a 3D road map image is displayed as a 2D image by 2D data acquisition to generate a 3D intermediate image.
When road map images are generated as represented by imaging for TAVI, it is important to generate a more suitable mask image to display an image with an improved image quality. Note that, a road map image can be also generated by a medical image processing apparatus connected to an X-ray imaging apparatus as well as an image processing function provided with an X-ray imaging apparatus.
Accordingly, an object of the present invention is to provide a medical image processing apparatus, a medical image processing method, and an X-ray imaging apparatus which can display compound images with a more improved image quality using X-ray contrast image data and X-ray fluoroscopic image data of an object.